Compressed-Liquid Density Measurements of Four Polyol Ester-Based Lubricants

A vibrating-tube densimeter has been used to measure compressed-liquid densities of the fluids pentaerythritol tetrapentanoate (POE5), pentaerythritol tetraheptanoate (POE7), pentaerythritol tetranonanoate (POE9), and a fully qualified lubricant within a temperature range of 270 to 470 K at pressures within 0.5 to 50 MPa. The compressed-liquid densities of the lubricants studied cover a density range from 829 kg/m³ to 1063 kg/m³. The data have been extrapolated to atmospheric pressure and correlated with a Racket equation and the compressed-liquid density data have been correlated to Tait equations for comparison to existing literature data.